Rolls Royce/Allison 501-K Gas Turbine Antifouling Compressor Coatings Evaluation

Abstract

The Naval Surface Warfare Center, Carderock Division (NSWCCD) Gas Turbine Emerging Technologies Code 9334 was tasked by NSWCCD Shipboard Energy Office Code 859 to research and evaluate fouling resistant compressor coatings for Rolls Royce Allison 501-K Series gas turbines. The objective of these tests was to investigate the feasibility of reducing the rate of compressor fouling degradation and associated rate of specific fuel consumption (SFC) increase through the application of anti-fouling coatings. Code 9334 conducted a market investigation and selected coatings that best fit the test objective. The coatings selected were Sermalon for compressor stages 1 and 2 and Sermaflow S4000 for the inlet guide vanes and remaining 12 compressor stages. Both coatings are manufactured by Sermatech International, are intended to substantially decrease blade surface roughness, have inert top layers, and contain an anti-corrosive aluminum-ceramic base coat. Sermalon contains a Polytetrafluoroethylene (PTFE) topcoat, a substance similar to Teflon, for added fouling resistance. Tests were conducted at the Philadelphia Land Based Engineering Site (LBES). Testing was first performed on the existing LBES 501-K17 gas turbine, which had an uncoated compressor. The compressor was then replaced by a coated compressor and the test was repeated. The test plan consisted of injecting a known amount of salt solution into the gas turbine inlet while gathering compressor performance degradation and fuel economy data for 0, 500, 1000, and 1250 KW generator load levels. This method facilitated a direct comparison of compressor degradation trends for the coated and uncoated compressors operating with the same turbine section, thereby reducing the number of variables involved. The collected data for turbine inlet, temperature, compressor efficiency, and fuel consumption were plotted as a percentage of the baseline conditions for each compressor. The results of each plot show a decrease in the rates of compressor degradation and SFC increase for the coated compressor compared to the uncoated compressor. Overall test results show that it is feasible to utilize antifouling compressor coatings to reduce the rate of specific fuel consumption increase associated with compressor performance degradation.

Simulation of a mixed-conducting membrane-based gas turbine power plant for CO2 capture: system level analysis of operation stability and individual process unit degradation

“…Further details on degradation of gas turbines can be found in a recently published review [22]. Conventional GTPPs are usually cleaned on a monthly basis, but more frequent washing procedures may be required, for instance on-line washing scheduled after 50 h and off-line washing after 500 h [24,29]. In an on-line washing procedure, the GT is running at high speed, whereas in an off-line wash, the engine is rotated at 20-50% of design speed [20,25] with a fuel supply being off [30].…”

Off-design performance prediction of gas turbines without the use of compressor or turbine characteristics

“…Buildup of fouling cannot be prevented since there is no such environment that is without contaminants of some sort. The only methods of combating fouling are by performing a compressor cleaning, by selecting more effective inlet filters, or by applying anti-fouling coating to blade surfaces (Caguiat, 2003). More effective inlet filters tend to be expensive and tend to have a higher head loss.…”